Very high-speed railroad train sets travel along some lines equipped as conventional catenaries of variable height. The contact force of the pantographs of these train sets on the catenary wires changes considerably when strong gusts of wind disrupt the collection of the current. At the present time, the speed of the train sets is reduced in the event of a meteorological warning announcing these gusts of wind.
It is therefore expedient to have a device allowing the pantograph to be made less sensitive to transitory squalls by controlling the force exerted on it.
A possible solution to this problem would involve executing a closed-loop control of the bearing force of the pantograph on the catenary wire. The aim would then be to design an electromechanical actuator device controlled permanently according to well-known control techniques. The actuator member can be electrical, hydraulic or preferably pneumatic.
However, in the specific context of railroad train set equipment, a closed-loop control device has a number of disadvantages of which the following may be mentioned:
the need for permanent energy consumption to maintain the control in respect of a pneumatic actuator, this resulting in an appreciable consumption of air,
possible problems of stability of the control and reliability of the elements of the closed loop,
the relative complexity of such a device and a high cost.